// 变量的用法
$highlight-color: #f90;
$basic-border: 1px solid  black;
#app {
    background-color: $highlight-color;
  	border: $basic-border;
      .container {
          font-size: 20px;
          
      }
      a {
        color: pink;
        background-color: orangered;
        &:hover {
            color: white;
        }
    }
}     